Packaging apparatus



Nov. 11, 1958 L. E. DOWD 2,859,576

PACKAGING APPARATUS Filed March 22, 1956 INVENTOR. AAURf/VCE E. DOWD ATTORNEY 2,859,576 PACKAGING APPARATUS Laurence E. Dowd, Park Forest, 11L, assignor to Swift & iCompany, Chicago, ilL, a corporation of Iliinois Application March 22, 1956, Serial No. 573,236 1 Claim. (Cl. 53-370) This invention relates in general to the packaging of objects in flexible wrapping m aterial s, 'and particu. larly to an nnproved methodandjapp'aratusljfo a'ckaging food products in closelyadlieringflexible wiappers.

The advantages of packaging food products, such as boneless hams, Canadian-style bacon, and poultry, in flexible wrapping materials which are tightly drawn about the surfaces of the product are many, including a more attractive package and better preservation of the color, aroma, and flavor of the product.

Packages having these cling-type wrappers are formed by wrapping a thin sheet of flexible, shrinkable wrapping material around the product and subjecting the product and wrapped to a source of heat to cause the wrapper to contract and adhere intimately to the surface of the product. Generally, the packaging material is wrapped around the product and the protruding ends are twisted to draw the wrapping material in tightly around the product. In twisting the protruding ends of the wrapper, the ends are grasped in the hands of the operator and the body of the wrapped product is contacted transversely of the length thereof by a rotating belt or drum. Because the flexible wrapper presents a smooth surface to the revolving drum or belt, it has been necessary in prior art apparatus to provide frictional means on the drums, such as ribs, teeth or corrugations, to insure that the package will be rotated by the drum or belt. These prior art devices are not satisfactory, however, in spinning heavy, odd-shaped items, such as square or rectangular meat loaves. Heavy irregularly shaped objects bounce about on the surface of the wheel, causing bruising of the product, and the requirement that the operator support the greater part of the weight of the object results in excessive operator fatigue.

It is, therefore, an object of this invention to provide an improved wrapping and twisting apparatus in which the contacting surface for spinning a package is characterized by superior properties of softness and resiliency as well as good frictional engagement.

Additional objects if not specifically set forth herein will be readily apparent to one skilled in the art from the detailed description which follows:

In the drawings:

Figure 1 represents a side view of a single wheel package twisting device.

Figure 2 shows a side view of the double wheel embodiment of the package twisting apparatus.

Figure 3 shows a cross section through the wheel covering shown in Figures 1 and 2.

In accordance with the present invention, a sheet of shrinkable thermoplastic wrapping material is wrapped around a meat product such as boneless ham, allowing for a slight overlap in the longitudinal edges of the wrapper. The ends of the film protruding beyond the end of the product are then held rigid and the encased product is contacted transversely of the length thereof with a rotating wheel. After several very rapid revolutions of the product the ends of the packaging material become tightly 2,859,576 1C6 J"Pate te ..N9 i.l .l-

twisted drawing the wrapper inwardly into intimate contact with the surface of'theproduct. Thewrapped package is then subjected toai'soiirceiof'heat s'uclri as a steam chamber, o pp in er at around v200 F. Thehot water or stream treatment shrinks the wrapper, into close conformance with e'surraee of theproduct. I 'Th e heat the preferred form of this treatment also shrinks and locks the twisted end, portions of the wrapper. Thejshrinkablej plastic material used in :vntionisahlm fo r ned of a 'copolymer 'of vinylidene "chloifid e and viny l chloride known unde'r the trademark Saran Wr a althofigli variousothe'r heat-shrinkable thermoplastic compositions sold under trademarks Pliofilrn, Mylar",andpolyethylenefmay be employed. A f "I Referring, now tothe drawings: There isfillus'trat'ed'in Figure l the single wheel em- I bodiment of the device ofithis myemidh: A framelgenorally 10; carries a shaft iljltwhich is rridunted bnjtlie frame by means" of pillow 'block bearings asst 12'. "Fixedly mounted on the shaft is a wheel 13 and a pulley 14. The surface of wheel 13 is covered with a layer of foam rubber or other resilient foam-like material 15 of a type providing good frictional engagement. A belt 16 connected to a pulley 17 on a source of power, motor 18, is also connected to pulley 14 on the twisting wheel.

Figure 2 shows the double wheel modification for twisting the ends of a package. A frame generally 25 supports a pair of shafts 21 and 22, each shaft riding in a pair of pillow block bearings. One of each of these pairs of bearings is shown at 23 and 24. A driven rotating wheel 25 is mounted on shaft 21 and an idler wheel 26 is attached to shaft 22. A pulley 27, fixedly attached to driven wheel 25 is operatively connected by belt 28 to a pulley 29 on the output shaft 30 of a speed reducer shown generally as 31. The surface of the rotating wheel and the surface of the idler wheel are covered with a layer 32 of an elastic material such as foam rubber or other equivalent resilient material. The speed reducer is operatively connected to a motor 33 or other suitable source of power by means of a belt 34 connecting the motor with the input shaft 35 of the speed reducer.

Wheel-covering'materials found well suited to the device shown herein may be selected from any of a number of foamed polymeric substances such as polyurethane foams, polyethylene foams, water-softened regenerated cellulose sponge, polyvinyl chloride foams, and foam rubber. These foamed elastoplastic compositions because of their softness and elasticity effectively cushion the package, permitting the operator to use the wheel to support a greater portion of the package weight than has been possible heretofore. It is thus possible for an operator to handle a greater number of heavy, odd-shaped packages than has been possible previously. An added advantage inherent in these cushioning compositions is the resistance to damage by contaminants such as grease or oil.

An important feature of the wheel structure of the device of this invention is the plano-concave form of the surface provided by the wheel covering material. This is clearly shown in Fig. 3 which represents a cross section through the spinning wheel surface, the surface of the wheel being shown as 36 and the covering as 37. The concavity in the wheel surface (assumed under the pressure of the contacting object) provides for a substantial degree of conformity between the operating surface and the package, and also limits lateral movement and bouncing of the package. An advantage inherent in the structure of the cushion covered wheel is the rigid backing which the surface of the wheel provides. This represents a substantial improvement over belts used to spin packages. While belts provide the necessary elasticity and softness, difficulty is encountered in control of the spinning operation since there is no rigid backing present.

The thickness of the wheel covering material may vary between about 1 inch and about 3 inches although a layer of from about m-m inches has been found most satisfactory.

It is possible in following the teaching of this invention to rapidly and economically wrap products in cling-type packages in a continuous production line operation with a minimum of operator fatigue. The cushioning effect of the solid based resilient foam material, coupled with the upward thrust of the wheel as illustrated in the single wheel embodiment of the apparatus shown in Fig. 1, relieves the operator of most of the weight of the product.

Obviously, many modifications and variations of the invention as hereinbefore set forth may be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claim.

I claim:

The improvement in apparatus for use in entubing objects in closely adhering wrappers and twisting the ends of said wrappers which comprises: a wheel rotatable about its axis; a layer of elastoplastic material, selected from the group consisting of polyurethane foam, polyethylene foam, water-softened regenerated cellulose sponge, polyvinyl chloride foam, and foam rubber, secured about the outer periphery of said wheel, said layer being characterized by a generally concave depression across its outer surface; and means to rotate said wheel whereby an object within a loose wrapper when held against the concave surface of said elastoplastic material will be rotated in a direction opposite said wheel to enable the ends of said wrapper to be twisted closed.

References Cited in the file of this patent UNITED STATES PATENTS 1,173,274 Igou Feb. 29, 1916 1,289,930 Schlereth Dec. 31, 1918 2,071,300 Garnmeter Feb. 16, 1937 2,340,260 Clunan Jan. 25, 1944 2,346,613 Rumsey Apr. 11, 1944 2,538,025 Moore et a1 Jan. 16, 1951 2,598,073 Rumsey May 27, 1952 

